1. Field of the Invention
The present invention relates to electric cartridge fuses having a core means associated therewith for assisting in quenching of the arc formed upon interruption of the fuse. More specifically, it is directed to a means for assuring the position of such an arc-quenching core with respect to the fusible element of such an electric fuse.
2. Description of the Prior Art
U.S. Pat. No. 3,935,553, entitled "Cartridge Fuse for DC Circuits," issued on Jan. 27, 1976, is assigned to the same assignee as the present invention. The disclosure of the above-identified U.S. Pat. No. 3,935,553 is hereby incorporated by reference in its entirety.
As set forth in U.S. Pat. No. 3,935,553, it has been found particularly advantageous in a number of electrical cartridge fuse designs to incorporate a core, made from a gas evolving electric insulating material, in close operative engagement with certain portions of the fusible elements of such electric fuses. Proper positioning of such gas evolving cores permits arc-quenching gasses to be released by the core upon melting of the fusible element at a particularly advantageous location wherein it will assist in extinguishing the arc while not contributing to generating, under certain operating conditions, undesirable excessive pressures within the fuse. Experience with fuses of the type disclosed in the '553 patent has shown that the axial positioning of the gas evolving core or cores with respect to the fusible element with which it is associated is extremely critical.
One technique which has evolved for assuring axial positioning of the gas evolving cores in such fuses has been to deform portions of the fusible element surrounding the core in order to retain the axial position of the cores. Such a solution has proved to be an undesirable approach to the problem and it is towards means for readily assuring precise axial positioning of the cores in such a fuse that the present invention is directed.